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How to: Create a Basic RSS Feed

Windows Communication Foundation (WCF) allows you to create a service that exposes a syndication feed. This topic discusses how to create a syndication service that exposes an RSS syndication feed.

To create a basic syndication service

  1. Define a service contract using an interface marked with the WebGetAttribute attribute. Each operation that is exposed as a syndication feed should return a Rss20FeedFormatter object.

    [ServiceContract]
    public interface IBlog
    {
        [OperationContract]
        [WebGet]
        Rss20FeedFormatter GetBlog();
    }
    
    
    Bb412174.note(en-us,VS.100).gifNote:
    All service operations that apply the WebGetAttribute attribute are mapped to HTTP GET requests. To map your operation to a different HTTP method, use the WebInvokeAttribute instead. For more information, see How to: Create a Basic WCF Web HTTP Service.

  2. Implement the service contract.

    public class BlogService : IBlog
    {
        public Rss20FeedFormatter GetBlog()
        {
            SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"));
            feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
            feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
            feed.Description = new TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF");
    
            SyndicationItem item1 = new SyndicationItem(
                "Item One",
                "This is the content for item one",
                new Uri("http://localhost/Content/One"),
                "ItemOneID",
                DateTime.Now);
    
            SyndicationItem item2 = new SyndicationItem(
                "Item Two",
                "This is the content for item two",
                new Uri("http://localhost/Content/Two"),
                "ItemTwoID",
                DateTime.Now);
    
            SyndicationItem item3 = new SyndicationItem(
                "Item Three",
                "This is the content for item three",
                new Uri("http://localhost/Content/three"),
                "ItemThreeID",
                DateTime.Now);
    
            List<SyndicationItem> items = new List<SyndicationItem>();
    
            items.Add(item1);
            items.Add(item2);
            items.Add(item3);
    
            feed.Items = items;
    
            return new Rss20FeedFormatter(feed);
        }
    }
    
    
  3. Create a SyndicationFeed object and add an author, category, and description.

    SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"));
    feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
    feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
    feed.Description = new TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF");
    
    
  4. Create several SyndicationItem objects.

    SyndicationItem item1 = new SyndicationItem(
        "Item One",
        "This is the content for item one",
        new Uri("http://localhost/Content/One"),
        "ItemOneID",
        DateTime.Now);
    
    SyndicationItem item2 = new SyndicationItem(
        "Item Two",
        "This is the content for item two",
        new Uri("http://localhost/Content/Two"),
        "ItemTwoID",
        DateTime.Now);
    
    SyndicationItem item3 = new SyndicationItem(
        "Item Three",
        "This is the content for item three",
        new Uri("http://localhost/Content/three"),
        "ItemThreeID",
        DateTime.Now);
    
    
  5. Add the SyndicationItem to the feed.

    List<SyndicationItem> items = new List<SyndicationItem>();
    
    items.Add(item1);
    items.Add(item2);
    items.Add(item3);
    
    feed.Items = items;
    
    
  6. Return the feed.

    return new Rss20FeedFormatter(feed);
    
    

To host a service

  1. Create a WebServiceHost object.

    Uri baseAddress = new Uri("http://localhost:8000/BlogService");
    WebServiceHost svcHost = new WebServiceHost(typeof(BlogService), baseAddress);
    
    
  2. Open the service host and wait until the user presses ENTER.

    svcHost.Open();
    Console.WriteLine("Service is running");
    
    XmlReader reader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog");
    SyndicationFeed feed = SyndicationFeed.Load(reader);
    Console.WriteLine(feed.Title.Text);
    Console.WriteLine("Items:");
    foreach (SyndicationItem item in feed.Items)
    {
        Console.WriteLine("Title: {0}", item.Title.Text);
        Console.WriteLine("Summary: {0}", ((TextSyndicationContent)item.Summary).Text);
    }
    Console.WriteLine("Press <enter> to quit...");
    Console.ReadLine();
    svcHost.Close();
    
    

To call GetBlog() with an HTTP GET

  1. Open Internet Explorer, type the following URL, and press ENTER: http://localhost:8000/BlogService/GetBlog. The URL contains the base address of the service (http://localhost:8000/BlogService), the relative address of the endpoint, and the service operation to call.

To call GetBlog() from code

  1. Create an XmlReader with the base address and the method you are calling.

    Uri serviceAddress = new Uri("http://localhost:8000/BlogService/GetBlog");
    
    
  2. Call the static Load method, passing in the XmlReader you just created.

    XmlReader reader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog");
    SyndicationFeed feed = SyndicationFeed.Load(reader);
        
    
    

    This invokes the service operation and populates a new SyndicationFeed with the formatter returned from the service operation.

  3. Access the feed object.

    Console.WriteLine(feed.Title.Text);
    Console.WriteLine("Items:");
    foreach (SyndicationItem item in feed.Items)
    {
        Console.WriteLine("Title: {0}", item.Title.Text);
        Console.WriteLine("Summary: {0}", ((TextSyndicationContent)item.Summary).Text);
    }
    
    

Example

The following is the full code listing for this example.

using System;
using System.Xml;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Syndication;
using System.ServiceModel.Web;
using System.Collections.ObjectModel;
using System.Collections.Generic;

namespace Service
{
    [ServiceContract]
    public interface IBlog
    {
        [OperationContract]
        [WebGet]
        Rss20FeedFormatter GetBlog();
    }

    public class BlogService : IBlog
    {
        public Rss20FeedFormatter GetBlog()
        {
            SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"));
            feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
            feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
            feed.Description = new TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF");

            SyndicationItem item1 = new SyndicationItem(
                "Item One",
                "This is the content for item one",
                new Uri("http://localhost/Content/One"),
                "ItemOneID",
                DateTime.Now);

            SyndicationItem item2 = new SyndicationItem(
                "Item Two",
                "This is the content for item two",
                new Uri("http://localhost/Content/Two"),
                "ItemTwoID",
                DateTime.Now);

            SyndicationItem item3 = new SyndicationItem(
                "Item Three",
                "This is the content for item three",
                new Uri("http://localhost/Content/three"),
                "ItemThreeID",
                DateTime.Now);

            List<SyndicationItem> items = new List<SyndicationItem>();

            items.Add(item1);
            items.Add(item2);
            items.Add(item3);

            feed.Items = items;

            return new Rss20FeedFormatter(feed);
        }
    }

    public class Host
    {
        static void Main(string[] args)
        {
            Uri baseAddress = new Uri("http://localhost:8000/BlogService");
            WebServiceHost svcHost = new WebServiceHost(typeof(BlogService), baseAddress);

            try
            {
                svcHost.Open();
                Console.WriteLine("Service is running");

                XmlReader reader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog");
                SyndicationFeed feed = SyndicationFeed.Load(reader);
                Console.WriteLine(feed.Title.Text);
                Console.WriteLine("Items:");
                foreach (SyndicationItem item in feed.Items)
                {
                    Console.WriteLine("Title: {0}", item.Title.Text);
                    Console.WriteLine("Summary: {0}", ((TextSyndicationContent)item.Summary).Text);
                }
                Console.WriteLine("Press <enter> to quit...");
                Console.ReadLine();
                svcHost.Close();
            }
            catch (CommunicationException ce)
            {
                Console.WriteLine("An exception occurred: {0}", ce.Message);
                svcHost.Abort();
            }
        }
    }
}

Compiling the Code

When compiling the preceding code, reference System.ServiceModel.dll and System.ServiceModel.Web.dll.

See Also

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